Di2 confusion

thetrifatlete
thetrifatlete Posts: 3
in Workshop
Hi all, I am scratching my head with a Di2 set-up.

I purchased a secondhand groupset for my girlfriend and fitted it all to the bike. I plugged the charger in and no light, so I assumed the (older style) battery was kaput, so I bought a new one. Still no charging light.
Tested the charger on my system, it worked, so systematically tried junction boxes and wires and still nothing. Tried my battery, nothing. At some point, I had the RD unplugged and I noticed the FD worked. Plug the RD back in and the whole system is dead. Unplug and FD works.
Wondered if the RD was in crash mode but holding the button didn't work, so I'm thinking I have a duff RD. I take the RD off my TT bike, so I can get Katherine's bike running and nothing, the system is dead. As a test, I unplug the FD and the RD works. Plug in FD and the system is dead.

What is going on, please? Both derailleurs work but only if one of them is plugged into the system. Have the both plugged in and it seems to kill the whole system.

Thanks in advance.

Comments

  • trevor.hall12
    trevor.hall12 Posts: 470
    I would test the 4 way box first

  • trevor.hall12
    trevor.hall12 Posts: 470
    trevor.hall12 said:

    I would test the 4 way box first

  • thetrifatlete
    thetrifatlete Posts: 3
    Done that, Trevor, I have tried two Bs. Have also tried two As. Same issue, works with one mech but not two.
  • trevor.hall12
    trevor.hall12 Posts: 470
    Are all the parts firmware up to date ?
  • trevor.hall12
    trevor.hall12 Posts: 470
    When it's plugged in or on the app does it show all components connected ?
  • trevor.hall12
    trevor.hall12 Posts: 470
    Is it in manual mode and not syncro
  • thetrifatlete
    thetrifatlete Posts: 3
    Think I may have got to the bottom of the issue. I have a 6870 RD but a 6770 FD. I didn't think it would make a difference but apparently it does.

    As for firmware, I need to bring my work laptop home, as my home laptop is Mac.
  • pilot_pete
    pilot_pete Posts: 2,120
    Yes, that is your problem. If you had an old battery, with old firmware you might have been able to get them to work together, but the latest (and for some time) firmware updates since 11sp became the norm will prevent you running this combo.

    A Shimano technician responded on another forum with this… https://www.roadbikereview.com/threads/di2-ultegra-fd-6870-and-rd-6770-compatibility-issue.328349/
  • Wheelspinner
    Wheelspinner Posts: 6,659
    ^^ Blimey.

    Another good reason to avoid Di2.
    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • MattFalle
    MattFalle Posts: 11,644
    Wheelspinner said:

    ^^ Blimey.

    Another good reason to avoid Di2.

    this, totally. it all seems just so much freakin' hassle.

    another part of the fun of tinkering with bicycles taken away in the modern search for a lifestyle.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    not to mention this......




    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    and this.



    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    £3k plus for a groupset that is heavier, less reliable, you can't use how you want, will become outdated within 4 years, isn't actually any better than the equivalent mechanical and a factory has complete and total control over.

    but hey .....
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • paulwood
    paulwood Posts: 231
    but hey.....I love my Di2

    Each to his or her own
  • First.Aspect
    First.Aspect Posts: 16,697
    I'm starting to think about hoarding parts for rim braked bikes. Think wheels from China that are last year's Enve's will be available for some time, but Di2 shifters with wires and brake cables?

    I suppose Campag will be a last hold out for intransigent Italians....
  • pblakeney
    pblakeney Posts: 26,973
    You can still get square taper cranksets. If there is a market then it will be filled.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • First.Aspect
    First.Aspect Posts: 16,697
    pblakeney said:

    You can still get square taper cranksets. If there is a market then it will be filled.

    Sure, but will they be any good?

    And I'm less convinced about groupsets. You can still get friction shifters, but a back compatible STI lever?
  • pblakeney
    pblakeney Posts: 26,973
    First.Aspect said:

    pblakeney said:

    You can still get square taper cranksets. If there is a market then it will be filled.

    Sure, but will they be any good?

    And I'm less convinced about groupsets. You can still get friction shifters, but a back compatible STI lever?
    Modern cranksets are far from issue free. Customer's choice.
    No comment on STI as I am a Campagnolo luddite. 😉 Plenty old spares for them.
    Bottom line, all you are trying to do is move a chain from one cog to another. It isn't rocket science.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • MattFalle
    MattFalle Posts: 11,644
    It isn't rocket science but it seems a shocking amount of people are prepared to give up all mix and matching and future proofing and easy to repair and cheaper and lighter and functionally just as good in the name of marketing based technology.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    First.Aspect said:

    I'm starting to think about hoarding parts for rim braked bikes. Think wheels from China that are last year's Enve's will be available for some time, but Di2 shifters with wires and brake cables?

    I suppose Campag will be a last hold out for intransigent Italians....

    this, exactly what i was talking about with a friend yesterday.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • MattFalle
    MattFalle Posts: 11,644
    it does seem that what used to be the norm - paying more to get lighter and more reluable - has now turned into paying more to get heavier and less reliable....
    .
    The camera down the willy isn't anything like as bad as it sounds.

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